Electronic devices such as cell phones, laptops, or tablets contain batteries that must be re-charged periodically. Although battery technology is continuously improving, consumers use these devices constantly and demand an increasing amount of capability from them, which quickly drains the batteries. Charging of such devices is thus an important and necessary part of their operation. Such devices are usually purchased together with an included charger, sometimes referred to as a power supply or adapter. Conventional chargers are AC adapters with prongs that plug into a wall outlet to access the alternating current (“AC”) power supply of a building. They typically have internal circuitry that converts the AC power to direct current (“DC”) power and lowers the voltage so that it is useable by the device. A cord connected to the adapter plugs into the device and delivers power to it. The cords, especially those of cell phone chargers, are generally short, such as around three feet or less in length. Short cords are generally preferred: since the devices are highly portable, it is desirable for the chargers to be highly portable as well, and longer cords make the charger cumbersome and difficult to carry. However, whether the cords are long or short, keeping track of them can sometimes be difficult: because chargers are designed to be portable like the devices they charge, users often travel with them, plug them into different locations, and eventually lose them. It can be incredibly frustrating to be unable to find a charger when one's mobile device is low on power.
The availability of outlets ultimately determines where a user can charge his or her device. Whatever the length of the charger cord, charging of the device is limited to locations within that distance of an outlet. The user must plug the device into the charger and leave it in that location for some time as the battery charges. A user might also want to connect the device to external power not just for charging, but to avoid running on battery power. For example, running on external power is desirable while using a device for a demanding task like streaming a movie or video chatting, and, as a result, some people prefer to operate their mobile devices while plugged in to avoid draining the battery. Buildings, however, are constructed with a limited number of outlets and are generally not designed to make charging a mobile device easier. This limits the options for locations in which a device may be connected to power. Outlets may be occupied by other devices or appliances, or may be too far from a desired location for the user. A user streaming video on a couch may not be able to watch while connected to power if the closest outlet is more than three feet from the couch.
Installing more outlets in a building is possible but requires small-scale demolition, reconstruction, and labor and skill. Running power to a location that is beyond the cord length of an outlet requires the use of an extension cord, but those are not desirable in many environments, especially home or office, because they are not aesthetically pleasing and can be an obstacle such as a trip hazard. An improved system for supplying power to mobile electronic devices is needed.